1. Field of the Invention
The invention relates to equipment for smoking cigarettes, using a smoking machine which is activated as a function of a test-person's recorded inhaling, or draw-profiles.
Such apparatus is used to collect the substances contained in the cigarette smoke to subsequently feed them to an analysis stage. In this manner it is possible to compare various kinds of cigarettes and also various batches of one kind of cigarette as regards the smoke composition. It is essential in this respect that the smoking process correspond as much as possible to the habits of the smoker and that, therefore, various pauses, durations and intensities in the inhaling be considered.
2. Description of the Prior Art
Equipment of the cited species is known from the book SMOKING BEHAVIOR by Raymond E. Thornton, Churchill Livingstone publishers, 1978, pp 277 through 288. The pressure and volume profiles of the smoking gas generated when a test person smokes a cigarette are measured and converted into electric potential values, subjected to an analog-digital conversion and stored on magnetic tape, also including the pauses in inhaling; this stored draw profile can be read out from the magnetic tape to activate a smoking machine.
By means of a partial vacuum, this smoking machine generates the required air flow for the smoking of a cigarette, this flow being controlled by an analog valve.
The potential values obtained and recorded in the above-mentioned manner are used to control the valves inserted into the smoking channels between a partial-vacuum chamber and a cigarette, the valves opening or closing more or less depending on the particular values of the recorded draw profile and hence draw an amount of gas through the cigarette which corresponds to the test-person's draw profile.
The known apparatus suffers from the drawback that the application of the recorded draw profile and especially the control of such a smoking machine is very costly; and in spite of this high cost, the profile generated in the smoking machine will not always correspond in all aspects to the test-person's draw profile. Difficulties occur for instance, when a double-draw should be reproduced as occurs when starting a cigarette. In such a double-draw, there is a very rapid rise and fall of the draw profile that can hardly be simulated by means of valves.